Urine test predicts smokers' lung cancer risk

Quick to light up despite the potential risks? Take note: there may be a way to rapidly predict your chances of developing lung cancer – and provide yet more incentive to kick the habit. Researchers have discovered that smokers who excrete high levels of two tobacco metabolites (chemicals produced when the body breaks down tobacco) in their urine are up to 8.5 times more likely than those who excrete low levels to develop lung cancer.

"If we can identify a smoker with a high level of metabolites, and down the road they have a higher risk of lung cancer, public health workers can get them motivated to quit smoking,” lead researcher Jian-Min Yuan, a cancer epidemiologist at the University of Minnesota in Minneapolis, told Bloomberg News.

Yuan and his team studied the urine chemicals in 491 smokers participating in the Shanghai Cohort Study and the Singapore Chinese Health Study, 246 of whom developed lung cancer during a 10-year follow-up. Suspecting that a tobacco metabolite called 4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), which triggers lung cancer in lab animals but whose effect on humans is unknown, would be a good predictor of lung cancer, the scientists divided study subjects into three groups: those with high, medium and low NNAL levels.

They found that smokers with the highest NNAL levels in their urine were twice as likely as those with the lowest amounts to develop lung cancer. When the researchers included a second metabolite called cotinine in their analysis, they found that those with the highest levels of both NNAL and cotinine in their urine were 8.5 times more likely to develop the disease.

A standard urine metabolite test for smokers would probably cost $100 to $120 and take a few years to develop, Yuan told HealthDay News, but he is optimistic that the use of such a test would push at-risk smokers to stop.

Tobacco use leads to 440,000 deaths in the US every year, according to the American Cancer Society. The org notes that one in four Americans continues to puff away even though smoking is the No. 1 cause of cancer deaths in the U.S.